Establishing native forest vegetation after a disturbance (e.g. a mine) or in areas where forest vegetation did not previously exist can be costly and time-consuming. Seeds or propagules for native forest vegetation may not be obtainable from traditional sources such as greenhouses, nurseries or seed cooperatives. As an increasing amount of forests are being disturbed there has been a corresponding increasing societal and regulatory demand for re-establishment of native forest vegetation.
Collection and planting of soil plugs can establish native boreal plants; however, this method is very labor intensive and costly. An additional cost associated with planting soil plugs is the additional time required to hand dig holes for planting the plugs on the land where native forest vegetation is desired. Soil plugs are not compressed and transporting plugs without causing damage to the integrity of the plug is difficult.
The use of forest floor material, such as the organic matter horizon that accumulates on the mineral soil surface under forest vegetation (referred to as LFH), which can contain thousands of seeds and vegetative propagules from many different native forest species, has been shown to be an effective way of establishing native forest vegetation. Forest floor material also contains nutrients, micro-organisms and soil fauna and provides water holding capacity which improves the growth of forest species.
Currently, forest floor material may be salvaged prior to the initiation of anthropogenic disturbances. The bulked material is then transported to land where native forest vegetation is desired and a continual layer of the forest floor material is spread on the surface of the land. However, the forest floor material is usually stockpiled and stockpiling reduces the viability of the seeds and vegetative propagules. Additionally, there may not always be stockpiled material at the time it is needed for reclamation.
Salvaging forest floor material from other locations and transporting to the land where native forest vegetation is to be established could overcome the above limitations; however, transporting the required quantity of material is often not economically feasible and the material may still have to be stored, reducing the viability of seeds and vegetative propagules.
Compacting or compressing the forest floor material reduces transportation costs. In its bulked form, forest floor material has a lower density and vehicles used for transportation can be loaded to their maximum volume (but not to their maximum weight). If the material is compressed, then the vehicles may be loaded to both their maximum volume and weight. Compressed forest floor material creates additional benefits for plant establishment, such as improved moisture retention, nutrient concentration and soil to propagule contact.
A continual layer of compressed forest floor material may not need to be applied to land where the native forest vegetation is desired, as there is a higher concentration by volume of seeds and vegetative propagules contained in the compressed material (and in the bricks, slabs, wafers, pellets or any other shape of the compressed material, referred to herein as “Products”) allowing the material to be evenly distributed with spaces between each Product. Vegetation established from the Products could fill in the spaces between the Products
Direct placement of forest floor material at shallow depths does not provide good seed/vegetative propagule to soil contact; therefore many seeds/vegetative propagules dry out and die. Large equipment cannot move through existing reclaimed forested areas without disturbing the trees and other plants.
Attempts have been made to mix the forest floor materials with a mulch or hydro mulch, which does not preserve all seeds and vegetative propagules in the material. Processing forest floor materials results in the destruction of vegetative propagules. These methods require specialized amendments and equipment for processing and application and the specialized equipment likely cannot move through existing reclaimed forested areas.
Related patent literature includes EP 0092990; US 20130020738; EP 2457438; US 20020078623; EP2452555; U.S. Pat. No. 4,517,764; and U.S. Pat. No. 4,332,093.